Use of a microwave oven for cooking or reheating coated products is problematic because the substrate is heated from the inside by the microwave radiation generating steam which may damage the batter and crumb coatings. Conventional coated products are therefore unsuitable for use in microwave ovens.
Many food materials, for example natural muscle of poultry, fish or red meat or vegetable or processed foods contain a large percentage of water. Most fresh foods contain more than 60% water. Some of this water is bound, that is tightly attached to the constituent cells. The remaining mobile water is available and can be frozen. If a food product is frozen to a core temperature of between −1° C. and −30° C. or lower and is placed and irradiated in a microwave oven, the microwave energy will be primarily absorbed by the frozen available water. Whereas in conventional cooking heat is applied from the exterior, in microwave cooking heat is generated from within. The process of heating can be very rapid so that available water is converted into steam. When a food product is allowed to stand after heating in a microwave oven, water can continue to be expelled from the product. This is particularly noticeable for example when heating frozen fish muscle. The loss of water causes any food coating, particularly a batter, pastry or breadcrumb coating to become soggy and unpalatable. In addition the core of the substrate may become dry due to the loss of water.
WO 93/03634 describes a method of producing a coated foodstuff which may be reheated by microwave irradiation, the method comprising: applying to the foodstuff a predust; applying a batter to the predusted foodstuff; frying the battered foodstuff, and cooling the fried product.
WO 95/30344 describes a process for microwaveable coated food products comprising the steps of predust application, batter application, crumb application, flash frying, freezing and packaging.
WO 97/03572 describes a process for microwaveable coated food products, such as chicken nuggets, comprising the steps of predust application, batter application, crumb application, flash frying, freezing and packaging.
WO 2010/001101 describes a method of manufacture of a crumb coated food product comprising the steps of: forming an aqueous mixture comprising: flour, sodium bicarbonate, optional additives and water; adding the mixture into an extruder; adding an aqueous gelling agent to the extruder; extruding the resultant mixture at a temperature greater than 100° C. to form an expanded porous product; drying the product, and milling the dried product to form a crumb. The crumb so obtained is particularly suitable for use in the preparation of coated food products that are cooked or reheated from a frozen state using a microwave oven.